Research And Design Of Photonic Crystal Fiber Polarization Devices

Photonic crystal fiber polarization filters and photonic crystal fiber polarization splitters have great application prospects in optical communication because of their small size,good performance and flexible design.In this paper,based on the finite element method,two kinds of photonic crystal fiber polarization filters and one kind of photonic crystal fiber polarization splitter are designed by using COMSOLMultiphysics multi-field coupling software.The influence of structural parameters on the filtering characteristics and polarization characteristics and their change rules are systematically studied,and the optimization principle of structural design is established.It provides theoretical support for the design and fabrication of photonic crystal fiber polarizers.Firstly,a single-channel photonic crystal fiber polarization filter is designed based on the principle of surface plasmon resonance.The working wavelength is 1310 Nmx and the loss value in Y polarization direction is 1920.36 d B/cm and 3.29 d B/cm,respectively.When the length of the fiber is 1000μm,the crosstalk value of the filter is 1665.14 d B,and the operating bandwidth of less than-20 d B reaches 779 nm.Secondly,a two-channel photonic crystal fiber polarization filter is proposed to achieve two-channel filtering at 1310 nm and 1550 nm.When the incident wavelengths are 1310 nm and 1550 nm,the losses in the Y polarization direction are 1496.46 d B/cm and 1847.97 d B/cm,respectively,and the losses in the X polarization direction are 1.98 d B/cm and 16.00 d B/cm,respectively.When the length of the fiber is 1000μm,the two corresponding cross-talk values are-1298.09 d B and-1591.23 d B respectively,and the operating bandwidth of less than-20 d B exceeds 1000 nm.Finally,a photonic crystal polarization beam splitter is designed.When the working wavelength is 1310 nm,the length of the beam splitter is 27.87234μm,the corresponding extinction ratio is-152.40 d B,and the working bandwidth length is 152 nm when the working wavelength is less than-10 d BWhen the working wavelength is 1550 nm,the length of the beam splitter is 15.59356μm,the extinction ratio reaches-137.21 d B,and the working bandwidth of less than-10 d B is 200 nm.The three kinds of photonic crystal fiber polarization devices have excellent performance and can achieve good filtering or beam splitting effect.They have great application prospects in all optical networks and optical communication fields.